Analysis On Influence Of Traction Transformer Connection To Harmonic And Negative Sequence Of Yun Nan Grid And Electrified Railway

As the traction power supply system loads are asymmetric, so it makes three-phase current unbalance in both the traction transformer high-voltage and low-voltag, and produce negative sequence current on the system bus side. Negative sequence current system of public connection point can generate the negative sequence voltage, and flow to the other load through the common connection point, increase the power loss, some devices can not work properly. AC and DC electric locomotive is a typical rectifier load, the harmonics generated by electric locomotive will cause interference and pollution to the public power.The traction transformer is the core equipment that was connected traction power supply system and power system. The main functions are the completion of voltage transformer and power transmission. The wiring mode of the traction transformer not only affect the transformer capacity, but also determine power system influence degree that was created by traction load. Analyzing the impact of the power system that was caused by traction power supply system, such as calculation of traction load harmonic distribution in power system, traction power system cause three-phase load imbalance in power system, Traction transformer wiring is particularly important.The article use the summing-up model of power system components, apply computer program with Matlab software to calculate distribution of negative sequence and harmonics that were generated by traction load in the grid. When conducting power flow simulation, traction transformer harmonic correction method is more concerned about. In this paper, several harmonic correction method bringed into use the more commonly at present are amended to the three traction transformer in the article, simulate and make outcome.Combine with the measured data of Electrified railway in Yunnan Province, use of calculation program, simulate and analysis distribution of harmonic and negative sequence of the Yunnan Power Grid Chuxiong regional sub-grid. Harmonic Distribution Simulation:In the case of determining compensation pattern, simulate the different traction wiring on the impact of the harmonic. Simulation of the distribution of negative sequence:when it is alternation commutation phase and no commutation phase, analyze different traction wiring on the impact of negative sequence; when different load was used, analyze traction wiring on the impact of negative sequence...